The Competition Commission of Singapore (CCS) fined 12 motor vehicle traders for breaching the Competition Act.
In a news release on Thursday, it said the motor traders had engaged in an anti-competitive agreement to suppress bids at public auctions of motor vehicles over a period of three years from January 2008 to March 2011.
It has fined them a total of $179,071 for the infringements with fines ranging from $50,733 to $8,000.
The three traders that received the highest fines were Pang's Motor Trading, Tim Bock Enterprise and Kiat Lee Machinery.
The CCS had begun investigations in May 2010 after it received information on alleged bid-rigging activities at public auctions of motor vehicles held by government agencies.
It found the 12 traders had entered into an agreement to refrain from bidding against each other at public motor vehicles auctions. Instead, a sole bidder would bid for the vehicles before the 12 traders conducted their own private auctions for vehicles won.
From 2008 to 2011, the 12 firms won about 700 motor vehicles during 53 physical and online auctions.
The CCS said the bid-suppression had distorted vehicle trade and was a "serious infringement" of the Competition Act.